Multilayer bonding ribbon

Abstract

A bonding wire takes the form of a ribbon, and a bond includes such a bonding wire. The bonding wire includes at least two layers having different current carrying capacity.

1 . A bonding wire, comprising: 
 at least two layers made of different materials, the bonding wire taking the form of a ribbon.    
     
     
         2 . The bonding wire according to  claim 1 , wherein the layers exhibit different current carrying capacities.  
     
     
         3 . The bonding wire according to  claim 1 , wherein the layers have different melting points.  
     
     
         4 . The bonding wire according to  claim 1 , wherein the layers have difference conductivities.  
     
     
         5 . The bonding wire according to  claim 1 , wherein the layers have different at least one of (a) bending resistances, (b) tensile strengths and (c) elasticities.  
     
     
         6 . The bonding wire according to  claim 1 , wherein the layers have different thicknesses.  
     
     
         7 . The bonding wire according to  claim 1 , wherein the bonding wire includes at least three layers.  
     
     
         8 . The bonding wire according to  claim 1 , wherein the bonding wire includes two outer layers and at least one inner layer arranged between the outer layers, the inner layer having a greater current carrying capacity than the outer layers.  
     
     
         9 . The bonding wire according to  claim 8 , wherein the outer layers have a lower melting point than the inner layer.  
     
     
         10 . The bonding wire according to  claim 8 , wherein one of (a) the inner layer has at least one of (i) a higher conductivity, (ii) a lower bending resistance, (iii) a lower tensile strength and (iv) a lower elasticity than the outer layers and (b) the outer layers have at least one of (i) a higher conductivity, (ii) a lower bending resistance, (iii) a lower tensile strength and (iv) a lower elasticity than the inner layer.  
     
     
         11 . The bonding wire according to  claim 8 , wherein the outer layer encloses the inner layer over an entire periphery.  
     
     
         12 . The bonding wire according to  claim 11 , wherein an average layer thickness of the outer layer is one of (a) between approximately 1 nm and 200 nm, (b) between approximately 15 nm and 30 nm and (c) between approximately 20 nm and 25 nm.  
     
     
         13 . The bonding wire according to  claim 8 , wherein an average layer thickness of the outer layer is less than 1/10 of an average thickness of the bonding wire.  
     
     
         14 . The bonding wire according to  claim 1 , wherein an average thickness of the bonding wire is approximately 25 μm to 300 μm.  
     
     
         15 . The bonding wire according to  claim 1 , wherein an average width of the bonding wire is approximately 50 μm to 1 mm.  
     
     
         16 . A bond between two contact surfaces, wherein the contact surfaces are interconnected by at least one bonding wire, the bonding wire including at least two layers made of different materials, the bonding wire taking the form of a ribbon.  
     
     
         17 . The bond according to  claim 16 , wherein the contact surfaces are bonded by an ultrasonic weld.